ABSTRACT

Landsat is one of a number of satellites launched by various nations in order to provide remote sensing imagery to the public sector that can be used for a multitude of practical applications. The latest U.S. satellite (Landsat 5) was placed in a repetitive, circular, sun-syncronous near polar orbit on March 1, 1984 and furnishes data from seven bands in the 0.5 to 12.5 micrometer region. While not possessing the spatial resolution ability of a number of systems launched by foreign governments, Landsat 5 is the only system that can providelong term, high quality, color data that can be used for many geological and environmental investigations.

Using the USGS-developed Global Land Information System (GLIS), the Internet can be used to select those images that are most ideal for a particular investigation. Images acquired prior to September 1985 are available from the USGS (EROS Data Center) while those since that date are provided by a private firm (EOSAT).

A series of such images has been used as part of a major study directed toward assessing sedimento- logical and environmental processes taking place in Mobile Bay, Alabama and the adjacent Mobile River Delta. The former is the second largest estuarine complex in the United States (largest in the entire Gulf of Mexico) and one that has been heavily environmentally impacted; the latter is the largest inland delta system in North America and the largest wetlands area in the State of Alabama. Landsat 5 imagery has been invaluable in identifying sources of thermal pollution, classifying different wetland environments, developing sediment budget maps, assessing sediment sources and distribution patterns, and in identifying changes in shorelines and river flow patterns that have taken place in historical times. The wealth of information that can be gleaned from such photographs gives true meaning to the statement "a picture is worth a thousand words."